This invention relates to a motion-tracking instrument assembly. The device may be used in the collection of data geometrically characteristic of or defining a surface. More particularly, the device is connectable to a computer for providing the computer with electrically encoded data derived from and in part specifying a three-dimensional surface or curvilinear contour of an object. Alternatively, the device is utilizable to produce a controlled motion, for instance, of a tool or instrument. The invention is particularly useful in the practice of dentistry.
U.S. Pat. No. 5,569,578 discloses a system for effecting a desired modification in the shape of a pre-existing object to which access is restricted. The system is particularly useful in the practice of dentistry to effect the preparation of a tooth for a filling, a crown or inlay or other restoration. The system of U.S. Pat. No. 5,569,578 includes a computer, a first data generating device, a second data generating device, a display, an instruction input device and an output device. The first data generating device is operatively connected to the computer for providing the computer with electrically encoded data specifying a three-dimensional surface of the object, while the second data generating device is operatively connected to the computer for providing the computer with electrically encoded data specifying a curvilinear contour of the object. The display is responsive to signals from the computer for displaying a three-dimensional graphic representation of the object in accordance with data from the first data generating device and the second data generating device. The instruction input device operatively serves for instructing the computer to modify the three-dimensional representation of the object on the display and for selecting a modification of the three-dimensional representation which represents a desired object preparation. The output device is operatively coupled to the computer for issuing an output signal to effectuate a limitation in motion of a preparation instrument relative to the object so that the object is provided with the desired object preparation.
The first data generating device of U.S. Pat. No. 5,569,578 includes a scanning component for optically scanning the three-dimensional surface of the object and transmitting a video signal of the three-dimensional surface to the computer. More specifically, the first data generating device includes a projection assembly for optically imposing a grid on the object""s three-dimensional surface. In using the first data generating device, an operator provides a reference distance at the three dimensional surface being scanned.
The second data generating device of U.S. Pat. No. 5,569,578 includes a manipulable stylus-type instrument having a distal tip engageable with the object and further includes a position detection assembly for monitoring the location of the stylus tip relative to the object and for feeding electrically encoded data regarding the stylus tip location to the computer. In a preferred embodiment of the second data generating means, the position detection assembly comprises what is called here a pantograph assembly that functions to duplicate motion. The assembly includes a pantograph extension rigidly connected to the stylus-type instrument and an optical scanner for tracking the location of a point on the pantograph extension and transmitting a resulting video signal to the computer.
The second data generating device of a shape modification system in accordance with the disclosure of U.S. Pat. No. 5,569,578 enables a dentist or other operator to obtain shape data about areas which are not optically accessible, for example, areas below the gum line of a tooth. Such information is necessary for enabling tooth preparation to extend below the gum line. The shape modification system further comprises a cutting instrument and a position detection assembly for monitoring the location of a tip of the cutting instrument relative to the object and for feeding data regarding the cutting tip location to the computer. The position detection assembly may take the form described above with reference to the stylus-type instrument of the second data generating device, i.e., it may include a pantograph extension connected to the cutting instrument and an optical scanner for optically scanning the location of a point on the pantograph extension and transmitting a resulting video signal to the computer.
As described in U.S. Pat. No. 5,569,578, a cutting tool attachment may be substituted for a stylus attachment on a handle, holder or frame member. Thus, the instruction input device may include a cutting instrument and position detection assembly for monitoring the location of a tip of the cutting instrument relative to the object and for feeding data regarding the location to the computer. The position detection assembly may be of the kind described hereinabove. Using a cutting tool such as a drill enables an operator such as a dentist to feed a desired depth to the computer. The depth is useable by the computer to select and/or calculate a suggested tooth preparation and to show the suggested preparation on the display.
Alternatively or additionally, the instruction input device includes a keyboard connected to the computer and/or a contact sensitive region of the display. In this case, for example, the desired depth of a tooth preparation may be entered numerically. In addition, the operator may inform the computer via the keyboard of the type of tooth preparation which is desired. If a tooth being worked on is to receive a crown, the operator or dentist informs the computer, in one procedure according to the invention, to remove a certain percentage (e.g., 10%) from all top and side surfaces of the tooth to the contour below the gum line defined by the second data generating device.
An object of the present invention is to provide a motion-tracking device utilizable in an input mode for sensing three-dimensional motion and utilizable alternatively or additionally in an output mode for producing three-dimensional motion.
Another object of the present invention is to provide such a device which generates three-dimensional contour data of an object such as a tooth.
A related object of the present invention is to provide a data-gathering device which incorporates a position detection assembly for monitoring the location of a stylus tip relative to an object and for feeding electrically encoded data regarding the stylus tip location to a computer.
Yet a further object of the present invention is to provide a device which is utilizable in the practice of dentistry to collect in situ information about tooth surfaces.
These and other objects of the present invention will be apparent from the drawings and descriptions hereof. Every object of the invention is attained by at least one embodiment of the present invention. However, not every embodiment will necessarily attain every objective set forth herein.
A dental instrument assembly comprises, in accordance with the present invention, a first frame, a second frame, a plurality of telescoping members each connected at one end to the first frame and at an opposite end to the second frame, a plurality of linear transducers each operatively coupled to a respective one of the telescoping members for generating a signal indicative of a degree of extension of the respective one of the telescoping members, a generally U-shaped bracket connected to the first frame for mounting the first frame to a row of teeth in a patient""s mouth, and a dental instrument or probe mounted to the second frame.
It is contemplated that the linear transducers are operatively connected to a computer programmed to track motion of the dental probe or instrument at least partially in response to signals from the linear transducers.
Pursuant to another feature of the present invention, the dental instrument or probe is detachably mounted to the second frame. More specifically, the dental instrument or probe may be slidably secured to an elongate arm in turn connected to the second frame. Where the elongate arm is connected to the second frame via a rotary joint, the dental instrument assembly further comprises a rotary transducer operatively linked to the rotary joint for generating a signal indicative of a degree of angular displacement of the arm about an axis.
In accordance with a further feature of the present invention, a plurality of independently operable drive elements are operatively connected to the telescoping members for automatically varying degrees of extension of the telescoping members. It is contemplated that the drive elements are connected to a computer for controlling the degrees of extension of the telescoping members. Where the dental instrument or probe is mounted to the second frame via a linkage having a predetermined number of degrees of freedom of motion, the dental instrument assembly may additionally comprise a number of additional drive elements operatively connected to the linkage for automatically varying an operational configuration of the linkage.
A dental instrument assembly comprises, in accordance with another embodiment of the present invention, at least two multipod devices each including a first frame, a second frame, a plurality of telescoping members each connected at one end to the first frame and at an opposite end to the second frame, and a plurality of linear transducers each operatively coupled to a respective one of the telescoping members for generating a signal indicative of a degree of extension of the respective one of the telescoping members. The instrument assembly of this other embodiment of the present invention further comprises a generally U-shaped bracket connected to the second frame of one of the multipod devices for mounting that second frame to a row of teeth in a patient""s mouth. A dental instrument or probe is mounted to the second frame of another of the multipod devices. The first frames of the multipod devices are at least indirectly mounted to a stationary fixture and thus at least indirectly connected to each other.
A numerically controllable tool assembly comprises, in accordance with a further embodiment of the present invention, a first frame, a second frame, a plurality of telescoping members each connected at one end to the first frame and at an opposite end to the second frame, a plurality of drive elements each operatively coupled to a respective one of the telescoping members for automatically varying a degree of extension of the respective one of the telescoping members, a bracket connected to the first frame for mounting the first frame to an object, and a tool or operating instrument mounted to the second frame. The drive elements are connected to a computer for controlling the degrees of extension of the telescoping members. Where the tool or operating instrument is mounted to the second frame via a linkage having a predetermined number of degrees of freedom of motion, the numerically controllable tool assembly also comprises a number of additional drive elements operatively connected to the linkage for automatically varying an operational configuration of the linkage.